Relevance of interfacial viscoelasticity in stability and conformation of biomolecular organizates at air/fluid interface

M., Steffi Antony; Jaganathan, Maheshkumar; Dhathathreyan, Aruna

doi:10.1016/j.cis.2016.04.002

Cited by 5 publications

(2 citation statements)

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“…The intrinsic character of the protein plays an important role in the interfacial behavior of the molecule. For example, flexible proteins can unfold faster than globular proteins, affecting the rates of lowering of surface tension and the interfacial viscoelasticity. , The interfacial rheological properties of proteins have been well documented. − Similarly, colloidal properties, such as the charge distribution, are known to affect protein aggregation . To study the effects of agitation on aggregation, traditional methods involve the shaking of vials. , In the past, our group pinpointed the major cause of aggregation to be interfacial dilatation (area-change) and not shear flow .…”

Section: Introductionmentioning

confidence: 99%

Monoclonal Antibody Interfaces: Dilatation Mechanics and Bubble Coalescence

et al. 2018

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Monoclonal antibodies (mAbs) are proteins that uniquely identify targets within the body, making them well-suited for therapeutic applications. However, these amphiphilic molecules readily adsorb onto air-solution interfaces where they tend to aggregate. We investigated two mAbs with different propensities to aggregate at air-solution interfaces. The understanding of the interfacial rheological behavior of the two mAbs is crucial in determining their aggregation tendency. In this work, we performed interfacial stress relaxation studies under compressive step strain using a custom-built dilatational rheometer. The dilatational relaxation modulus was determined for these viscoelastic interfaces. The initial value and the equilibrated value of relaxation modulus were larger in magnitude for the mAb with a higher tendency to aggregate in response to interfacial stress. We also performed single-bubble coalescence experiments using a custom-built dynamic fluid-film interferometer (DFI). The bubble coalescence times also correlated to the mAbs aggregation propensity and interfacial viscoelasticity. To study the influence of surfactants in mAb formulations, polyethylene glycol (PEG) was chosen as a model surfactant. In the mixed mAb/PEG system, we observed that the higher aggregating mAb coadsorbed with PEG and formed domains at the interface. In contrast, for the other mAb, PEG entirely covered the interface at the concentrations studied. We studied the mobility of the interfaces, which was manifested by the presence or the lack of Marangoni stresses. These dynamics were strongly correlated with the interfacial viscoelasticity of the mAbs. The influence of competitive destabilization in affecting the bubble coalescence times for the mixed mAb/PEG systems was also studied.

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Section: Introductionmentioning

confidence: 99%

Monoclonal Antibody Interfaces: Dilatation Mechanics and Bubble Coalescence

et al. 2018

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“…Additionally, as noted below, interfacial viscoelasticity is important to a number of applications, including the stability of multiphase formulations. 45 We found that acetal copolymers poly(1a-alt-3) 50 exhibited the viscoelastic behavior, with a crossover between the loss modulus G″ (indicative of viscous character) and the storage modulus G′ (indicative of elastic character) as frequency was increased. Moreover, the crossover frequency for the 3a copolymer was near the upper limit of the measurements at ∼60 rad/s, while the 3c and 3b copolymers displayed crossovers at ∼10 and ∼3 rad/s, respectively (Figure 6).…”

Section: ■ Introductionmentioning

confidence: 82%

Alternating Ring-Opening Metathesis Polymerization Provides Easy Access to Functional and Fully Degradable Polymers

Boadi

Zhang

et al. 2020

Macromolecules

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Polymers with hydrolyzable groups in their backbones have numerous potential applications in biomedicine, lithography, energy storage, and electronics. In this study, acetal and ester functionalities were incorporated into the backbones of copolymers by means of alternating ring-opening metathesis polymerization catalyzed by the third-generation Grubbs ruthenium catalyst. Specifically, combining large-ring (7–10 atoms) cyclic acetal or lactone monomers with bicyclo[4.2.0]oct-1(8)-ene-8-carboxamide monomers provided perfectly alternating copolymers with acetal or ester functionality in the backbones and low to moderate molecular weight distribution (D̵ M = 1.2–1.6). Copolymers containing ester and acetal backbones hydrolyzed to significant extent under basic conditions (pH 13) and acidic conditions (pH ≤ 5), respectively, to yield the expected byproducts within 30 h at moderate temperature. Unlike the copolymer with an all-carbon backbone, copolymers with a heteroatom-containing backbone exhibited the viscoelastic behavior with crossover frequency, which decreases as the size of the R group on the acetal increases. In contrast, the glass transition temperature (T g) decreases as the size of the R group decreases. The rate of hydrolysis of the acetal copolymers was also dependent on the R group. Thus, ruthenium-catalyzed alternating ring-opening metathesis copolymerization provides heterofunctional copolymers whose degradation rates, glass transition temperatures, and viscoelastic moduli can be controlled.

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